Players in the kapenta fishing industry are reportedly scrambling for Lake Kariba's Basin 5, amid fears of overfishing which could scuttle efforts to replenish fish stock.
Some rig crews are reportedly moving from Basins 3 and 4 to Basin 5, which is largely viewed as lucrative and closer to the market.
This has exerted pressure on the zone as crews seek better catches while cutting on costs.
Investigations have shown that the quest by rig crews to meet their daily catch targets has driven some of them to encroach into breeding areas.
This has resulted in the increase in smaller kapenta on the market, which points to disturbed reproduction and growth.
In view of the developments, the Zimbabwe Parks and Wildlife Management Authority (ZimParks) has issued a notice advising fishermen that there was no more room in Basin 5.
"There is no space for additional rigs in Basin Five, as a conservation measure no transfers into Basin Five are allowed," read a notice from ZimParks.
Indigenous Kapenta Producers Association member Mr Garikai Stande said the main contributing factor to overfishing in Kariba was poaching.
"People tend to go to breeding areas to harvest good catches and they end up engaging in illegal activities," he said.
"The fish is then sold to poachers."
Mr Stande said poaching was persisting because ZimParks previously punished the company instead of the perpetrator, while some unregistered rigs operated illegally.
Of major concern, he said, was encroachment into other basins.
"This came up because of the issue of speculators who had unlicensed boats, which fished anywhere in the lake and this led to the crowding of boats in one area for a long time," said Mr Stande.
Another operator Mr Eddie Chirayi confirmed that people were moving from Basins 3 and 4 in search of better catches, but denied that they were in Basin 5.
"It is true because in Basin 4, which is Chalala, the catches are pathetic and it is also the same with Basin 3," he said.
"So, people are moving to the boundaries hoping for a better catch. It's not that they're in Basin 5, but on the boundary."
ZimParks has acknowledged the demand for Basin 5 after it embarked on a seven-night moratorium which resulted in catches increasing from 88kg per night to 188kg.
Mr Stande said ZimParks should impose a three-month moratorium on fishing to allow the fish stock to replenish.